TY - JOUR A1 - Tsuprykov, Oleg A1 - Chen, Xin A1 - Hocher, Carl-Friedrich A1 - Skoblo, Roman A1 - Yin, Lianghong A1 - Hocher, Berthold T1 - Why should we measure free 25(OH) vitamin D? JF - The Journal of Steroid Biochemistry and Molecular Biology N2 - Vitamin D, either in its D-2 or D-3 form, is essential for normal human development during intrauterine life, kidney function and bone health. Vitamin D deficiency has also been linked to cancer development and some auto immune diseases. Given this huge impact of vitamin Don human health, it is important for daily clinical practice and clinical research to have reliable tools to judge on the vitamin D status. The major circulating form of vitamin D is 25-hydroxyvitamin D (25(OH)D), although it is not the most active metabolite, the concentrations of total 25-hydroxyvitamin D in the serum are currently routinely used in clinical practice to assess vitamin D status. In the circulation, vitamin D - like other steroid hormones - is bound tightly to a special carrier - vitamin D-binding protein (DBP). Smaller amounts are bound to blood proteins - albumin and lipoproteins. Only very tiny amounts of the total vitamin D are free and potentially biologically active. Currently used vitamin D assays do not distinguish between the three forms of vitamin D - DBP-bound vitamin D, albumin-bound vitamin D and free, biologically active vitamin D. Diseases or conditions that affect the synthesis of DBP or albumin thus have a huge impact on the amount of circulating total vitamin D. DBP and albumin are synthesized in the liver, hence all patients with an impairment of liver function have alterations in their total vitamin D blood concentrations, while free vitamin D levels remain mostly constant. Sex steroids, in particular estrogens, stimulate the synthesis of DBP. This explains why total vitamin D concentrations are higher during pregnancy as compared to nonpregnant women, while the concentrations of free vitamin D remain similar in both groups of women. The vitamin D-DBP as well as vitamin D-albumin complexes are filtered through the glomeruli and re-uptaken by megalin in the proximal tubule. Therefore, all acute and chronic kidney diseases that are characterized by a tubular damage, are associated with a loss of vitamin D-DBP complexes in the urine. Finally, the gene encoding DBP protein is highly polymorphic in different human racial groups. In the current review, we will discuss how liver function, estrogens, kidney function and the genetic background might influence total circulating vitamin D levels and will discuss what vitamin D metabolite is more appropriate to measure under these conditions: free vitamin D or total vitamin D. KW - 1,25(OH)(2) vitamin D KW - Bioavailable vitamin D KW - Calculated free 25(OH) vitamin D KW - Free 25(OH) vitamin D KW - Free vitamin D KW - Directly measured free vitamin D KW - Genetic polymorphism KW - Total 25(OH) vitamin D KW - Vitamin D-binding protein Y1 - 2107 U6 - https://doi.org/10.1016/j.jsbmb.2017.11.014 SN - 0960-0760 VL - 180 SP - 87 EP - 104 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Luo, Ting A1 - Chen, Xiaoyi A1 - Zeng, Shufei A1 - Guan, Baozhang A1 - Hu, Bo A1 - Meng, Yu A1 - Liu, Fanna A1 - Wong, Taksui A1 - Lu, Yongpin A1 - Yun, Chen A1 - Hocher, Berthold A1 - Yin, Lianghong T1 - Bioinformatic identification of key genes and analysis of prognostic values in clear cell renal cell carcinoma JF - Oncology Letters N2 - The present study aimed to identify new key genes as potential biomarkers for the diagnosis, prognosis or targeted therapy of clear cell renal cell carcinoma (ccRCC). Three expression profiles (GSE36895, GSE46699 and GSE71963) were collected from Gene Expression Omnibus. GEO2R was used to identify differentially expressed genes (DEGs) in ccRCC tissues and normal samples. The Database for Annotation, Visualization and Integrated Discovery was utilized for functional and pathway enrichment analysis. STRING v10.5 and Molecular Complex Detection were used for protein-protein interaction (PPI) network construction and module analysis, respectively. Regulation network analyses were performed with the WebGestal tool. UALCAN web-portal was used for expression validation and survival analysis of hub genes in ccRCC patients from The Cancer Genome Atlas (TCGA). A total of 65 up- and 164 downregulated genes were identified as DEGs. DEGs were enriched with functional terms and pathways compactly related to ccRCC pathogenesis. Seventeen hub genes and one significant module were filtered out and selected from the PPI network. The differential expression of hub genes was verified in TCGA patients. Kaplan-Meier plot showed that high mRNA expression of enolase 2 (ENO2) was associated with short overall survival in ccRCC patients (P=0.023). High mRNA expression of cyclin D1 (CCND1) (P<0.001), fms related tyrosine kinase 1 (FLT1) (P=0.004), plasminogen (PLG) (P<0.001) and von Willebrand factor (VWF) (P=0.008) appeared to serve as favorable factors in survival. These findings indicate that the DEGs may be key genes in ccRCC pathogenesis and five genes, including ENO2, CCND1, PLT1, PLG and VWF, may serve as potential prognostic biomarkers in ccRCC. KW - clear cell renal cell carcinoma KW - bioinformatics KW - differentially expressed genes KW - biomarkers KW - Kaplan-Meier plot Y1 - 2018 U6 - https://doi.org/10.3892/ol.2018.8842 SN - 1792-1074 SN - 1792-1082 VL - 16 IS - 2 SP - 1747 EP - 1757 PB - Spandidos publ LTD CY - Athens ER -